The invention relates to the storage of tire information from an RFID transponder in a sensor.
Vehicle tires, in particular automobile tires, are known that include an RFID transponder (also referred to as ID tag), which is typically inserted by the tire manufacturer in the process of producing the tire. This RFID transponder stores tire information, for example tire sidewall information, with which the tire sidewall is also labeled (for example, the width of the tire), and/or other tire-specific information. The RFID transponder is typically a passive RFID transponder which does not have its own energy source but rather is supplied with energy via the radio signal from an interrogating device. If energy in the form of an alternating magnetic field or electromagnetic radio waves is introduced into the RFID transponder from the outside, the transponder can transmit the stored data using a standardized data protocol. The LF band (30-500 kHz), for example, is used to transmit the data.
RFID transponders in tires are typically used for logistical purposes.
Tire pressure monitoring systems for monitoring the tire pressure in motor vehicles are also known. In the case of a directly measuring tire pressure monitoring system, use is made of a sensor which is fastened to the tire or to the rim, for example, records the air pressure of the tire and typically also the air temperature of the tire and transmits the data to a receiving unit in the vehicle by radio using a standardized protocol. The sensor generally includes a sensor battery for supplying energy. Alternatively, a piezo generator is also possible.
In addition to the logistical use of tire information, tire information stored in an RFID transponder can also be used, however, in the control of dynamic-movement functions, for example during steering adjustment, vehicle controller adjustment or chassis adjustment (for example, damper control). For this purpose, it is necessary for the tire information to reach the respective control device for the dynamic-movement function. In this respect, it is contemplated, for example, to use an RFID reader to read tire information from a tire having an ID tag when fitting the tires and to then store this information in a sensor with which the tire is equipped. The sensor can then subsequently provide the vehicle with this information by radio.
In this case, it should be ensured that the tire information actually matches the tire fitted to the vehicle and has not been mixed up.
If it cannot be ensured that the tire information transmitted to the vehicle matches the tire actually fitted to the vehicle, the tire information cannot be used to carry out or improve dynamic-movement functions which are critical to safety.
JP2006282091A describes a method for transmitting tire information, in which an RFID transponder transmits stored tire information to a sensor which is mounted on the rim and, in turn, provides the vehicle with the information.
The object of the invention is to provide a method for introducing tire information into a sensor without being mixed up and to specify a tire which is set up accordingly.
This and other objects are achieved according to the invention.
A first aspect of the invention relates to a method for storing tire information in a tire sensor. For this purpose, a tire sensor is fastened to a tire having a passive RFID transponder. The fastening can be carried out manually or by machine. The RFID transponder is then supplied with energy via an energy field (for example, via an electromagnetic or magnetic field), with the result that the RFID transponder emits the stored tire information.
If the tire sensor has determined that the tire sensor is fastened to the tire, the tire information is received and is permanently stored in the tire sensor. If this has not been determined, the tire information is indeed received but the tire information is rejected again. Alternatively, provision may also be made for the tire sensor to not receive the transmitted tire information at all in the first place in this case. If the tire sensor subsequently determines that the fastening has been detached, the tire information stored in the tire sensor is preferably deleted. This makes it possible to prevent the tire sensor from being detached from the tire and being used in a new tire, in which case the sensor transmits the tire information belonging to the old tire.
The tire information written to a tire sensor is preferably transmitted to the vehicle by the tire sensor and is then taken into account, for example, during a dynamic-movement function, for example during steering adjustment, vehicle controller adjustment or chassis adjustment (for example, damper control). It is also contemplated for this information to be used to specify the tire inflation pressure.
The method according to the invention makes it possible to deal with tire-specific data with process reliability in order to provide said data in the vehicle in a manner protected against being mixed up and misused. As a result, safety-relevant dynamic-movement functions can also access the tire data and these functions can be functionally configured and developed in a tire-specific manner.
The method according to the invention prevents, for example, the tire information read from a particular tire, for example during the fitting process, from being stored in a tire sensor which is installed in another tire type with different characteristic variables.
The term “permanent storage” means not only temporary storage of the tire information while receiving the tire information, but also longer-term storage (for example, in a non-volatile memory) for the purpose of subsequent use. The tire information is stored in an EPROM, an NVRAM or a flash memory, for example. However, it is not absolutely necessary for the stored tire information to still be present after the energy supply for the tire sensor has been detached.
According to one preferred embodiment, the tire sensor includes at least one electrical contact (preferably at least two electrical contacts), an electrical connection being produced via the at least one contact when fastening the tire sensor, which connection is used by the tire sensor to determine the fastening. At least two contacts are typically provided in this case, the at least two electrical contacts of the sensor being connected to one another via an electrical connection outside the sensor, for example, when fastening the tire sensor in the sensor holder. The connection may be a low-impedance connection, in particular a short circuit. However, the connection may also have a higher resistance value.
However, it would also be theoretically conceivable to use only a single contact to detect the fastening.
According to one preferred embodiment, a sensor holder which is connected to the tire is provided. The tire sensor is introduced into the sensor holder in order to fasten the tire sensor in the tire.
The sensor holder may be fastened on the inside tread of the tire, for example, in particular adhesively bonded in a ground outlet in the inside tread. The sensor holder may already include the RFID transponder. Alternatively, provision may be made for the sensor holder and the RFID transponder to be separate from one another. For example, the RFID transponder may be permanently vulcanized in the tire in this case and the location which is then used to fasten, in particular adhesively bond, the sensor module holder may be marked.
According to one advantageous embodiment, both the sensor and the sensor holder each include at least one electrical contact, the electrical contacts of the sensor and of the sensor holder touching one another when the tire sensor is being introduced into the sensor holder and an electrical connection being produced. This connection is used by the tire sensor to determine the fastening. For example, two electrical contacts of the sensor may be connected to one another (in particular with low impedance) via an electrical connection outside the sensor when the tire sensor is being introduced into the sensor holder. This is then detected by the tire sensor for the purpose of detecting the fastening. For example, provision may be made for the sensor holder to have the RFID transponder and for the two electrical contacts to be connected, in particular short-circuited, via a corresponding line on the RFID transponder when the tire sensor is being introduced into the sensor holder. Alternatively, provision may also be made for the RFID transponder to be separate from the sensor holder and for the two electrical contacts to be connected to one another, in particular short-circuited, via a corresponding line in the sensor holder when the tire sensor is being introduced into the sensor holder.
A second aspect of the invention is directed to a tire for a motor vehicle, in particular to an automobile tire. The tire includes a passive RFID transponder which stores tire information. A tire sensor which is fastened to the tire is also provided. The RFID transponder is set up to emit stored tire information when the RFID transponder is supplied with energy. The tire sensor is also set up to determine that the tire sensor is fastened to the tire and to receive the emitted tire information and to store it in the tire sensor if the tire sensor has determined that the tire sensor is fastened to the tire.
The tire preferably includes a sensor holder which receives the tire sensor.
The statements made above with respect to the method according to the invention in accordance with the first aspect of the invention also accordingly apply to the tire according to the invention in accordance with the second aspect of the invention.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.